The Israel Antiquities Authority got an interesting package from the U.S. recently, Archaeology News reported. It contained a piece of early medieval stonework and came with a note.

The note said that the sender, who apparently remained anonymous, had been an archaeology student 12 years ago and stole the stone from the excavation he was on so that he would have a memento with which to “pray for Jerusalem.” Instead, it made him feel guilty and so he decided to return it. Sometimes guilt takes a while to work.

At least this idiot had to pay a lot in postage. The stone weighed 21 kilograms (more than 46 pounds) and appears to be a portion of a marble column from the Umayyid Dynasty, a Muslim dynasty that ruled the region from 661 to 750 A.D. The Umayyids had the first major Muslim empire, ruling over a vast territory from their capital in Damascus. They were responsible for building two of the major Muslim sites in the holy city–The Dome of the Rock (pictured here) and Al-Aksa Mosque.

Israeli archaeologists believe the column came from a large palace complex built near the Temple Mount that served as the local seat of government.

As some travelers set off to volunteer at archaeological excavations this summer, this former archaeologist would like to remind them that stealing antiquities is not only immoral, but illegal, and could land you in jail. It will certainly get you an F in your archaeology class.